S-nitrophenyl carboxyalkyl disulfides



United States Patent l S-NITROPHENYL CARBOXYALKYL DISULFIDES Marvin Carmack, Bloomington, Ind., and John F. Harris, Jr., Wilmington, Del., assignors to the Trustees of the University of Pennsylvania, Philadelphia, Pa.

No Drawing. ApplicationSeptember 12, 1956 Serial No. 609,346

6 Claims. (Cl. 260-470) This invention relates to a new class of organic disulfides and to their preparation.

More specifically, this invention comprises unsymmetrical nitrophenyl disulfides of formula .and their salts and esters, where R is a nitro-substituted phenyl group and R is an open-chain hydrocarbon or an acyl-substituted open-chain hydrocarbon radical; and their preparation by the methods outlined below.

This application is a continuation-in-part of cope'nding United States application Serial No. 408,020, filed February 3, 1954, now abandoned.

The above-mentioned disulfides are conveniently prepared by reacting substantially equimolecular portions of a sulfenyl halide of formula RSX where R has the same significance as in formula 1 and X is halogen, preferably chlorine or bromine, with a mercaptoacid of formula where R has the same significance as in formula 1.

Some of the disulfides can also be prepared by reacting a dithiohalide of formula 4 RSZX of this invention are crystalline solids which are generally yellow in color. For the most part, they can be melted without decomposition. They are insoluble in water but yield water-soluble salts with alkali bases, such as sodium and potassium hydroxide. They are somewhat soluble in organic solvents, such as ether and benzene, from which they are conveniently recrystallized. Reduction of the nitrophenyl disulfides of the invention using, for example, zinc and hydrochloric acid will give an aminothiophenol. The following equation is illustrative of such reduction.

The following examples, in which parts are by weight,

2,849,479 Patented Aug. 26, 1958 illustrate the preparation of representative disulfides of this invention.

Example 1 This example illustrates the preparation of phenyl carboxymethyl disulfide,

One part of freshly distilled thioglycolic acid 'in about 10 parts of anhydrous ether was added to 2.6 parts of o-nitrobenzenesulfenyl chloride in about 60 parts of anhydrous ether. After standing for one hour, the solution was evaporated to dryness, leaving 3.14 parts of yellow residue. After several recrystallizations from benzene, the product, o-nitrophenyl carboxymethyl dio-nitrosulfide, was obtained as yellow prisms melting at 119- I This compound was also prepared by reacting o-nitrophenyldithiochloride with ketene in anhydrous ether, followed by hydrolysis of the adduct with cold water.

Calcd. for C8H7O4NS2I C, 39.17; H, 2.88; S, 26.14. Found: C, 39.20; H; 2.95; S, 26.23.

Example 2 This example illustrates the preparation of 2,4-dinitrophenyl carboxymethyl disulfide,

To 2 parts of 2,4-dinitrobenzenesulfenyl chloride in about 100 parts of anhydrous ether was added 0.4 part of thioglycolic acid dissolved in a few parts of ether. After the mixture stood a short while, the ether was removed by evaporation. The resulting solid was recrystallized from benzene, yielding 1.6 parts of 2,4-dinitrophenyl carboxymethyl disulfide as yellow plates melting at l38-139 C. Example 3 This example illustrates the preparation of 2,4-dinitrophenyl 4-carboxybutyl disulfide,

To 1.75 parts of 2,4-dinitrobenzenesulfenyl chloride in about 50 parts of anhydrous ether was added 1 part of delta-mercaptovaleric acid in 5 parts of ether. After cooling and filtering, there was obtained 1.98 parts of yellow solid melting at l22l24 C. After recrystallization from benzene, 2,4-dinitrophenyl 4-carboxybutyl disulfide was obtained as yellow prisms melting at 124 125 C.

Example 4 This example illustrates the preparation of ethyl alphao-nitrophenyldisulfidoacetoacetate, which has the formula I-OHz SSCHC O O C2115 To a solution of 2.16 parts of o-nitrophenyldithiochloride in about 30 parts of anhydrous ethylene chloride was added 4 parts of freshly distilled ethyl acetoacetate. The mixture was refluxed for three hours. At the end of the reflux period, the solvent was evaporated, leaving an oil. This oil solidified on standing to 2.58 parts of yellow solid melting at 81-82 C. After several recrystallizations from hexane, the compound, ethyl alpha-o-nitrophenyldisulfidoacetoacetate, was obtained as yellow prisms mixed with needles melting at 8283 C. Calcd. for C H O NS C, 45.70; H, 4.15; S, 20.33; terminal methyl, 9.54. Found: C, 45.80, 45.92; H, 4.34, 4.10; S, 20.98, 20.69; terminal methyl, 8.49.

The following are further examples of the novel compounds of our invention:

(1) 2,4-di'nitro-5-carboxypentyl disulfide (M. P. 117

(2) 2-nitrophenyl-S-carboxypentyl disulfide (M. P. 82

(3) 2,4-dinitrophenyl-3-carboxypropyl disulfide (4) 2-nitrophenyl-3-carboxypropyl disulfide (5) 2-nitrophenyl methoxycarbonylmethyl disulfide (6) 2,4-dinitrophenyl-Z-methoxycarbonylethyl disulfide (7) (4-nitrophenyldithio) acetic acid, sodium salt (8) (2-nitrophenyldithi0)propionic acid, potassium salt The fungicidal activity of the compounds of our invention has been demonstrated at low concentrations, say, of the order of 0.001 to 1% by weight. For example, when tomato foliage is sprayed with an 0.2% aqueous solution or suspension of 2-nitrophenyl carboxymethyl disulfide and (after the spray deposit dries), exposed to early blight fungus, it is found that the amount of infection is materially reduced as compared to untreated plants that are similarly exposed to early blight fungus.

The above description is intended to be illustrative only. Any modification of or variation therefrom which conforms to the spirit of the invention is intended to be included within the scope of the claims.

We claim:

1. An unsymmetrical nitrophenyl disulfide represented by the formula and its salts and esters, Where R is a nitro-substituted phenyl group having from 1 to 2 nitro substituents and R is a radical having from 1 to 5 carbon atoms and selected from the class consisting of an open-chain hydrocarbon and an acyl-substituted open chain hydrocarbon radical.

2. A compound of claim 1 where R is a dinitro-substituted phenyl group.

3. o-Nitrophenyl carboxymethyl disulfide.

4. 2,4-dinitrophenyl carboxymethyl disulfide.

omOss-omo 0 on mN-Oss-omo 0 on NaNOnlHCl HO- N=NOssoH,oooH

'rirOss-cmcoon 5. 2,4-din1'trophenyl 4-carboxybutyl disulfide. 6. Ethyl alpha-o-nitrophenyldisulfidoacetoacetate.

References Cited in the file of this patent UNITED STATES PATENTS Haddock et a1. Mar. 19, 1935 Kershaw May 26, 1936 OTHER REFERENCES Jocini et al.: Chem. Abst. 46, 4499 (1952). 

1. AN UNSYMMETRICAL NITROPHENYL DISULFIDE REPRESENTED BY THE FORMULA 